1. Field of the Invention
The invention relates to a window structure which includes a window frame having inner and outer portions supporting inner and outer windows, each of which windows includes at least one movable sash therein wherein the frame portions are rigidly connected together through an insulating member providing a thermal break therebetween extending completely around the window structure. The window structure further includes a sash coupler connected to the movable sash of the inner window and operably associated with the movable sash of the outer window for selective engagement therewith to permit movement of the movable window sash together.
2. Description of the Prior Art
In the past, metal window structures of, for example, the single-hung type as disclosed in U.S. Pat. Nos. 3,711,995 and 3,795,076, have been provided with a single window frame extending from the inside to the outside of the opening which is to be closed by the window structure. With such structure, connsiderable heat will pass from the inside to the outside of the opening closed thereby due to passage of heat through the frame members. Other difficulties also arise with such structure, such as undesirable temperatures on the interior or exterior of the frame members, resulting in condensation of moisture in undesirable locations and the like.
Wherein thermal barriers have been provided in prior window frames between the interior and exterior thereof and the thermal barriers have extended completely through the frame members and around the frame, they have in the past often not imparted the required rigidity to the resulting total frame, or have been lacking in required insulating value.
Also, prior thermal barriers in window frames have sometimes required undesirable tolerances in one or both of the window frame portions and/or an insulating member therebetween.
In most window structures, such as those disclosed in the above United States patents, the inner window and outer window, where one is provided, are only movable separately. Wherein windows have been secured together in the past for opening and closing movement together, the structure securing them together has not been releasable without tools and automatically reengageable.